Raspberry Pi microSD card performance comparison - 2015

This post's benchmarks were performed on a Raspberry Pi 2; for all the latest benchmarks, on Raspberry Pi 3 or later revisions, check out the official Pi Dramble microSD card Benchmarks page.

In my experience, one of the highest-impact upgrades you can perform to increase Raspberry Pi performance is to buy the fastest possible microSD card—especially for applications where you need to do a lot of random reads and writes.

There is an order-of-magnitude difference between most cheap cards and the slightly-more-expensive ones (even if both are rated as being in the same class)—especially in small-block random I/O performance. As an example, if you use a normal, cheap microSD card for your database server, normal database operations can literally be 100x slower than if you used a standard microSD card.

Because of this, I went and purchased over a dozen different cards and have been putting them through their paces. Here are the results of those efforts, in a nice tabular format:

Card Make/Model

hdparm buffered

dd write

4K rand read

4K rand write

OWC Envoy SSD (USB) 64GB

34.13 MB/s

34.4 MB/s

7.06 MB/s

8.20 MB/s

SanDisk Ultra Fit (USB) 32GB

31.72 MB/s

14.5 MB/s

4.99 MB/s

1.07 MB/s

Samsung EVO+ 32GB

18.45 MB/s

14.0 MB/s

8.02 MB/s

3.00 MB/s

Samsung Pro+ 32GB

18.46 MB/s

18.5 MB/s

8.10 MB/s

2.35 MB/s

Samsung Pro 16GB

18.39 MB/s

18.2 MB/s

7.66 MB/s

1.01 MB/s

Samsung EVO 16GB

17.39 MB/s

10.4 MB/s

5.36 MB/s

1.05 MB/s

SanDisk Extreme Pro 8GB

18.43 MB/s

17.6 MB/s

7.52 MB/s

1.18 MB/s

SanDisk Extreme 16GB

18.51 MB/s

18.3 MB/s

8.10 MB/s

2.30 MB/s

SanDisk Ultra 16GB

17.73 MB/s

7.3 MB/s

5.34 MB/s

1.52 MB/s

NOOBS (1.4, C6) 8GB

17.62 MB/s

6.5 MB/s

5.63 MB/s

1.01 MB/s

Transcend Premium 300x 32GB

18.14 MB/s

10.3 MB/s

5.21 MB/s

0.84 MB/s

PNY Turbo (C10 90MB/s) 16GB

17.46 MB/s

TODO

6.25 MB/s

0.62 MB/s

Toshiba 16GB

17.66 MB/s

11.2 MB/s

5.21 MB/s

0.21 MB/s

Sony (C10) 16GB

15.38 MB/s

8.9 MB/s

2.47 MB/s

0.24 MB/s

Kingston (C10) 16GB

17.78 MB/s

9.0 MB/s

5.75 MB/s

0.21 MB/s

Kingston (C10) 8GB

12.80 MB/s

7.2 MB/s

5.56 MB/s

0.17 MB/s

Nasya C10 16GB

16.05 MB/s

8.4 MB/s

2.28 MB/s

0.38 MB/s

No-name (C4) 4GB

13.37 MB/s

< 1 MB/s

< 0.1 MB/s

< 0.01 MB/s

After using most of these cards in different situations over the past year or so (some for Pis running MySQL, others for file shares, and yet others just doing data logging and web dashboard displays), I've also noted that reliability-wise, all of the 16 cards I've used so far (even the no-name C4 card) have been flawless.

However, judging by performance vs. price, there are a couple clear standout cards—one is the Samsung Evo+, which is the fastest card for random access by a mile. And this year, I've seen it on sale for $10-20 for 32 or 64 GB, so it's a steal. Other than that, I'd go with the SanDisk Extreme, as it can be had for about the same price, or the Samsung Evo (without the +), as it can be had for even less if you just need 8 or 16 GB.

Benchmarks

hdparm buffered

sudo hdparm -t /dev/mmcblk0

Rationale: hdparm gives basic raw throughput stats for buffered reads (by the disk/device itself). You could also test with -T instead of -t to test the OS filesystem cache performance (which allows the OS to dramatically speed up certain read operations), but for our purposes we just want to test the device itself.

Setup:

Install hdparm: sudo apt-get install -y hdparm

dd write

Rationale: dd simply copies data from one place (if) to another (of). If your filesystem caches are big enough, this is a pretty poor disk speed comparison test. Because of that, make sure that count is set to a parameter large enough to cause the OS to actually write data to the drive (e.g. 50k8k blocks ~= 400 MB, which shouldn't be able to be cached on a microSD card in a Pi!.

iozone 4K Random read/write

Rationale: iozone is a very robust filesystem benchmark tool, which does a lot of useful tests that make sure you're getting a broad overview of read and write performance for a variety of block sizes and situations. I like the lower block size random I/O tests especially, because many operations (like logging data, writing a row to an ACID-compliant database, or bulk loading of data) require as fast of small-block-size random I/O as possible.

Most cheap microSD cards, even if rated as being 100MB/sec+ class 10 cards, can't sustain anywhere near that rate when writing random data—especially on the Raspberry Pi's measly data bus. (Note that most of the above benchmarks, when run on a USB 3.0 card reader on my MacBook Air, show 5, 10, or 15 times greater performance in that environment).

Comments

You can use dd with "conv=fsync" to make sure cache is flushed to disk before dd exits, therefore eliminating cache size as a variable. This is a more meaningful test than just cached dd, which doesn't really indicate anything.

I've run all tests on a B+ and Pi 2, and almost all numbers were within a couple percentage points. Some sustained reads/writes were faster on the Pi 2 if caching was enabled (but I didn't include those results in these listings because they measure Pi performance more than SD cards).

Some random comments.. random read / random write are usually measured in kIOps;

I think when comparing media, the capacity (GB) is important.
Usually larger capacities (e.g., 16GB vs 32GB) use more flash dies, which means more operations can be performed in parallel. If you are comparing different capacities, you should include the capacity in the table.

Could you add the exact model of the cards? The marketing name are usually carried over several generations. When searching for SanDisk Ultra on Amazon you can get (for the 16 GB size) either SDSDQUAN-016G-G4A (rated with 48MB/s max speed) or
SDSQUNC-016G-GN6MA (rated 80MB/s), and the pictures seem identical (maybe a different shade of grey)...

I was surprised to read your comment that there was no difference in reliability between the cards. How long did you run reliability tests?

Weewx is software for weather stations, that writes to databases and logs about every 5 minutes. The cheap cards rarely survive more than a month or two. We don't know how long the best cards last, as after a year plus of testing, they are still going strong.

For three cards, I have more than one year of continuous logging data (each Pi was using an Apple 5V USB power adapter): the Samsung 16GB EVO, the Transcend Premium 300x 32GB, and the Kingston C10 8GB. All three cards have performed flawlessly, writing a record into a MySQL database (that runs local on that card) every 30 seconds, 24x7.

I've also tested both the SanDisk Extreme and Samsung EVO for the past 3 months hosting http://www.pidramble.com/, on a 6-Pi2 cluster that runs Nginx, PHP, and MySQL. There are far fewer writes in that scenario, but logs are written to disk, and there's a small but steady amount of traffic to that site.

In all cases, I have not had any corruptions or failures with any of the cards. The only time I had any issue was with one SanDisk Ultra card, but I'm blaming that on a really flaky cheap micro USB power supply that I've since thrown away.

One problem with that test is that it didn't measure the cards being used from within a Pi itself (this can give vastly different results), and it also only ran the dd test (which tests large file write speed), but without the fsync option, which means buffering likely affected the results a little bit (made all the cards seem faster than they really were).

I've honestly never tried a Toshiba card, and haven't purchased a NOOBs card. Might need to pick one of each up :)

I have recently been doing some testing on microSDs for the Pis and have tested the Samsung EVO, Samsung EVO+ and the Samsung Pro Grade 3. I am not as savvy with the the testing tools, but one huge difference I noticed was the time it took to create the initial images.

I couldn't get iozone to run on the Pi, it compiled, but keeps saying the command isn't found.

I was able to run Crystal bench on them in a USB3 reader under Windows 7. A 1GiB sequential Read/Write with a 32 deep queue -
16gb EVO 46.77 MB/s and 12.61 MB/s
32gb EVO+ 89.21 MB/s and 30.38 MB/s
32gb Pro 90.24 MB/s and 77.28 MB/s
A big difference on the write side.

The Samsung Pro has 2 versions, Grade 1 and Grade 3. I got the Grade 3 card at Microcenter for $16. The SKU number on my receipt points to this item, http://www.microcenter.com/product/455064/32GB_Class_10_Pro_Micro_SD_Car.... But the picture and model number are wrong, that is the Grade 1 card. The Samsung Model number for the grade 3 card is MB-MG32EA/AM. The packaging on both the grade 1 & 3 cards claims 90 MB/s and 80 MB/s, and the price was the same. So I opted for the grade 3.

Interesting... the 4k random write number you're getting with the 32 GB card is about double what I tested with the Samsung Pro 16GB. Now you're making me want to get a 32 GB Pro card to see if there could be that dramatic a difference between different sizes!

Testing Kingston 8 GB vs 16 GB of the same model/series, I didn't see a significant difference... but that was Kingston.

I tried my Iozone install on regular Raspian, I will retry on Raspian Lite. I am very interested to see exactly how much of a bottle neck the Pis i/o system is.

When testing the 32gb Pro on an i7 based desktop, in a USB3 reader, the 32gb Pro card produces results similar to a 7200rpm spinning disk on a SATA bus in Crystal Bench! But I don't expect the Pi to be nearly as efficient. Just like a fast SSD can saturate the bus, there is going to be a point of diminishing return. However I wonder if cpu power is the primary limiting factor on random access?

I haven't been able to find the Pro+ line on sale and in stock anywhere, but someday I'll find one and test it. All these cards are purchased out of my discretionary personal money :)

For Lexar, I've so far been incredibly unimpressed with every card I've used from them (same as Sony)—random I/O has always been abysmal, and I've decided to stop wasting $10 per card to test their cards, and won't be convinced otherwise unless/until they want to send me a free sample that's not terrible :)

Could you please also measure the cards on a real linux host, to get a better comparison? This way we could say "okay on raspberry its different" and not "hm it might be tool related comparison".

Also another question:
Did you measure multiple times?
I also noticed a lot of speed differences between running the commands on the real tty1, a virtual terminal and via ssh. tty1 was the fastest of course.

Yeah it would be cool if you could give a bit more infos about those two models, since most people here who saw this on hackaday might now buy one of those two cards. And you know it makes a lof of difference, buying the right card.

Yes, every test was run 4 times, with the first result discarded, and with a completely pure/clean fresh Raspbian Lite install straight to the card being tested, which was always in the microSD slot on the Pi (not in a USB card reader).

Every test was run straight from boot (after raspi-config was run and a reboot), on tty1 using a keyboard/monitor plugged straight into the Pi.

Either card would be great on a Pi, but you're correct in that some cards like the Pro+ may give better results on a fast desktop machine with a USB 3.0 card reader. I'll try to do some tests on my Mac when I get a chance, but no promises!

I don't have an evo+, but the evo is an absolute beast at 4k and is without a doubt a great card to use. Running at 100mhz and using the same parameters for iozone, I get 14,340kb/s random read and 4,366kb/s random write (4k). An absolute beast.

Hi there
Ran your tests on my Toshiba Exceria 64Gb card (class 10, UHS-1) with my Pi3 overclocked at 100MHz. All results were competitive EXCEPT the 4k random write is atrocious
Toshiba Exceria 64GB 36.62MB/s 13.4MB/s 7.11MB/s 0.298MB/s
Based on your results have a 64GB Evo+ in the post as I use my Pi as my daily driver and have noticed occasional lags which I presume is the small file writes killing me.

I experienced the same horrible performance with the UHS-3 (2016 model?) version of the Toshiba Exceria. At 4k random writes, mine achieved only 88kb/s which is the worst I've ever seen on any modern microSD card.

I am interested in moving my ROOT partition to an external USB drive (most likely one of the nano/fit variants). It appears that the results of the Samsung Ultra Fit USB are worse than the EVO+ (which I am currently using). Will I see any performance gains using an external USB drive as my ROOT partiton on my RPi3 or is this a thing of the past that only applies to the RPi2?

Edit: I meant Sandisk Ultra Fit not Samsung, however, I am curious about the Samsung Fit as well. In fact, I'm open to suggestions about which would be the best nano/fit USB for the RPi3. Which one has the best random read/write performance. The Strontium Nitro looks promising...

Interestingly enough, I've purchased an 32GB EVO+ based on your results and also a new 32GB EVO Select to see how it compares in my Pi3. Both show dismal 4k write performance. These appear to be authentic Samsung parts, in full retail packaging ordered from Amazon. Their results are so close as to be identical, so I am wondering if the new EVO+ actually have EVO Select insides. They still meet the stated claims of 80MB read 20MB write, it is just the 4k that is terrible.

I verified it is not the Pi by using CrystalDiskMark under Windows 10. 4K performance is the same, although the sequential read performance is much higher due to running on a USB3 port. Don't you just love it when manufacturers change the internals of their product and still put the same label on it?

I also recently bought a Samsung Evo+ 32GB, but mine did not suffer from the performance issues you reported. Did your Evo+ really look like a Evo+ on the label and did you buy from a trustworthy seller?

I had Kingston (C10) 8GB and man it was so slow when I did a system upgrade or compiled something, it took long, too long. I upgraded to EVO+ and wow, this thing now works so fast, I enjoy using my Pi much more now.

Before you buy any type of memory always check the manufactures website for authorized sellers. Otherwise, you are risking buying a fake. It is very hard to tell the fakes from the real cards. The fakes will work but, probably not at their advertised speeds so, speed test your cards to check.

For example, on the Samsung site, Amazon is not listed as an authorized seller so, you're taking a risk of buying a fake card. I was going to put direct links to Samsung but not being allowed due to spam filters so, just search the manufaturers name and authorized sellers.

Every manufacturer should have a page listing their authorized sellers so, if you buy from one you know you're not getting a fake.

I bought a 32GB Evo+ off Aliexpress (2500 sold and extremely good 99.4% positive feedback) - looked like one of the most reputable sellers.

I'm fairly certain it's a fake. H2testw test fine. But slow performance in the Pi. Packaging also bit weird - Chinese and no adapter. Card looks identical - print quality etc. No way to tell them apart other than the serial number.

I bought a Samsung EVO+ 64 GB (MB-MC64DA/EU) from a reputable seller a few days ago and I also get shitty 4K random read/write speeds (latest Raspbian Jessie Lite on a Raspberry Pi 2 v1.1 with Iozone 4.65). Here are my speeds:

I am using some of these UHS-III cards, and while sustained read/write can hit ~100 MB/s (if you have a USB3 or USB-C reader capable of hitting those marks), random read/write is similar to the older cards—maybe 5-10 MB/s with a really good reader.